Pressure sensitive adhesive tape



. Oct. 29, 1935. F. w. HUMPHNER 2,019,010

PRESSURE SENSITIVE: ADHESIVE TAPE Filed June a, 1952 fikerzzr.

, lam 62mm nez d1? QSPP' Patented Oct. 29, 1935 UNITED STATES aoraom I rasssms SENSITIVE ADHESIVE urn Ferdinand W. Humphner, Oak Park, 111., author to Mid-States Gnmmodl Paper Co., Chicago, 111., a corporation of Illinois Application'June 8, 1932, Serial No. 618,129

Clalms.

This invention relates to pressure-sensitive adhesive tape and more particularly to tape having a treated cloth backing.

While pressure-sensitive adhesive tape provided with a sized cloth backing has been on the market for many years, such tape lacks qualities which are essential when the tape is employed for certain special uses. For example.

in the practice of painting or spraying with lacquer automobile bodies, etc., it is customary to attachmashs of paper and the like to the body by means of pressure-sensitive tape. Such tape must be sufilciently flexible to enable it to be applied to corners and curves on the body and, at the same time, the tape should be impervious or repellent to lacquers, paints, etc. A primary object of my invention is to provide a clothloached pressure-sensitive adhesive tape which has the above-mentioned qualities adapting it for use as a masking tape. Another object is to provide a shrunken cloth tape which is specially treated to provide a minimum oi voids in the tops and which serves as a suitable base for the application of the pressure=sensitive adhesive; objects and advantages will appear as the specification proceeds.

Elie invention is fully described in the follow= specification and shown in the accompanying drawing, in. whichl is a diagrammatic iii-3W of apparatus employed in the treating oi my improved cloth base; and 2 is a broken plan View of. the final product embodying my invention.

Broadly, the invention consists in treating a relatively loose fibrous or cloth well mechanically and with suitable materials in solution so as to shrink. the weband to produce a Web lease etc. and ordering a suitable fiat smiace for the application of pressure-sensitive adhesive. in diagrammatic illustration given in l, a

roll of relatively wide cloth iii is drawn by the roller it into a container i2 filled with treating solution. The web i then passes between the roller ii and a superposed roller it so as to flatten the web. The web it is then stretched hotness roller iii and a spaced roller i so as to oohtract the wide web into a relatively narrow strip. The narrow strip it is then drawn over roller it and wound upon the drivenroller it. The apparatus described is merely illustrative and it will be understood that the parts may be modified widely without departing from. the in= rentiou.

The wide web oi cloth stock may be of any is flexible, repellent to lacquer, point,

desired construction. A satisfactory starting material is 64 x 60 cloth; that is, cloth having sixty-four threads per inch running in one direction and sixty threads per inch running transversely thereof, such cloth being made of cotton or other 6' fibers.

The solution in container I2 preferably comprises materials which willcause the cloth to shrink while still rendering it flexible and im perviou-s to paints, lacquers and the like. llpre- 10 fer to employ gelatine or glues (hide or bone), mixed with water in the proportion of two parts of water to one part of gelatine or glue. This mass is brought to a solution by soaking and then brought to a liquid state by raising the temperature to approximately 150 F. and, when ready to use. additional materials are added as follows: Approximately 70% ct glycerine, by weight of dry glue, is mixed in thoroughly and then to the resulting mixture is added a gellingout reagent, such as aluminum sulphate, formaldehyoie, poraiormaldehyde, chromates. etc. The latter reagents serve to prevent absorption by the glycerine of additional water moisture as well as the loss of moisture already held by the glycerine, thus aiding in preserving the flexibility of the adhesiye tape.

In addition to the above, ll preier to add 9. vol-' atiie allrali, such as ammonia or other related organic allsalis, such aliralis serving to facilitate the shrinking of the cloth and assisting the glue solution in completely saturating the cloth fibers.

There are other combations which may be added for the purpose of loading the cloth or serving as a tiller, thus aiding in forming a sharp line or streight edge. It is important, when the tape is used in mashing automobile bodies, that the time have a straight edge to form the line 013 demarcation between the color tones applied to the body. For this purpose, clay or similar materiols oi sumcient fineness so that they do not detract from the bonding qualities of adhesiveelues my be added in suitable quantity, say 25% by weight oi dry glue. Also, as a substitute tor the glues, casein or starch etc. be eme5 ployed.

The tension placed upon the treated web it between rollers it and it, has a tendency to pull the threads of the cloth closely together, thus cooperating with the treating solution to eliminate the voids in the cloth. At the same time, this operation serves to limit the expansion of the product while allowing it sufilcient stretch to enable it to be conformed to angles, corners, etc. 0! the surface to which it is applied.

By passing the treated fabric through rolls, the fibers of the product are cemented down and when the solution dries, a flat surface is provided to receive the pressure adhesive. With ordinary treated or filled cloth, when the material is cut to a commercial size, the threads often pull loose, leaving a rough edge unsuitable for masking or other operations. The cloth treated in the above described manner prevents the unraveling of threads when the cloth iscut to a commercial size and leaves instead a straight even edge. The cloth is permanently saturated so as to be repellent to paints, lacquers, while at the same time, having flexible qualities and a minimum of voids. While the tape has great tensile strength, it may be readily severed by tearing it transversely by hand, the line of separation being straight and substantially at right angles to the tape body.

The finished product is illustrated in Fig. 2, in which the numeral l7 designates the impregnated or treated cloth base and i8 represents the pressure-sensitive adhesive applied to the base.

The pressure-sensitive adhesive may be of any suitable type and such an adhesive may be formed by methods which are well known in the art. For example, it may be formed by mixing crude rubber with zinc oxide, and the material may be maintained in its tacky, stage by mixture with suitable ingredients such as oil pitch, etc.

The pressure adhesive may be applied directly to the flattened surface of the cloth after the solution is dry, any suitablemethod of application being employed. When the tape is wound into a roll, the pressure-sensitive adhesive does not cling to the backing of the adjacent layer but is readily separated.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible, in view of the prior art.

I claim:

1. The method of forming pressure-sensitive I adhesive tape, comprising treating a loose fibrous web with a sealing and fixing solution, stretching said web to shrink the meshes thereof, and fix the same in shrunken form, drying the web and then coating one side thereof with pressuresensitive adhesive.

2. The method of forming pressure-sensitive adhesive tape, comprising treating a loose fibrous web with a solution for shrinking the same, and fixing it in shrunken form, stretching the web to 1 narrow the meshes thereof, drying the web and then coating one side thereof with pressure-sensitive adhesive.

3. The method of forming pressure-sensitive adhesive tape, comprising treating a relatively g0 wide'flbrous web with glue, stretching the web to narrow the meshes thereof, said glue serving to fix said web in shrunken form, drying the web and coating one side thereof with pressure-sensitive adhesive.

4.The method of forming pressure-sensitive adhesive tape, comprising treating a cloth web with gelatine, stretching the web to nar-' row meshes thereof, said gelatine maintainin said web in shrunken form, drying the web and a. coating one side thereof with pressure-sensitive adhesive. 1

5. The method of forming pressure-sensitive adhesive tape comprising treating a cloth web with glue, glycerine, and a gelling-out reagent, stretching the web to narrow the meshes thereof, drying the web while in stretched condition, and coating one side thereof with a pressure sensitive adhesive.

FERDINAND W. HUMPHNER. Q 

